What's the best way to build a road in the middle of a swamp? 

The Australian Road Research Board (ARRB) documented a visit to a Darwin construction site, outlining the process used to expedite building a road across an area of swampy land. 

As described in an ARRB blog article: 

"The process adopted by the NT Department involves deep soil stabilisation to provide a supporting foundation for road construction over the saturated soft silt deposits. Using a 45 tonne excavator with a grout injection and mixing attachment, the soft soil was stabilised with a GP cement slurry mixed to depths of up to 4m.

Using one such excavator working inwards from each end of the alignment, the soft soil stabilisation will cross the swamp in a matter of weeks as opposed to traditional consolidation methods which can take years. The cemented slurry sets up within three hours to meet the QA strength requirements with detailed records of the volume of slurry injected at each grid location and the resultant strength recorded with a cone penetrometer and shear vane. The stabilised material is covered with a geotextile then a capping layer prior to the normal earthworks and pavement construction." 

Take a look at ARRB's video: